Integrated multi-step gap fill and all feature planarization for conductive materials

ABSTRACT

A method and apparatus is provided for depositing and planarizing a material layer on a substrate. In one embodiment, an apparatus is provided which includes a partial enclosure, a permeable disc, a diffuser plate and optionally an anode. A substrate carrier is positionable above the partial enclosure and is adapted to move a substrate into and out of contact or close proximity with the permeable disc. The partial enclosure and the substrate carrier are rotatable to provide relative motion between a substrate and the permeable disc. In another aspect, a method is provided in which a substrate is positioned in a partial enclosure having an electrolyte therein at a first distance from a permeable disc. A current is optionally applied to the surface of the substrate and a first thickness is deposited on the substrate. Next, the substrate is positioned closer to the permeable disc. During the deposition, the partial enclosure and the substrate are rotated relative one another.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional of co-pending U.S. patentapplication Ser. No. 09/739,139, filed Dec. 18, 2000. The aforementionedrelated patent application is herein incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

[0002] The present invention relates to an apparatus and method fordeposition and planarization of a material, such as a metal, on asubstrate.

[0003] Sub-quarter micron multi-level metallization is one of the keytechnologies for the next generation of ultra large scale integration(ULSI). The multilevel interconnects that lie at the heart of thistechnology require planarization of interconnect features formed in highaspect ratio apertures, including contacts, vias, lines and otherfeatures. Reliable formation of these interconnect features is veryimportant to the success of ULSI and to the continued effort to increasecircuit density and quality on individual substrates and die.

[0004] In the fabrication of integrated circuits and other electronicdevices, multiple layers of conducting, semiconducting, and dielectricmaterials are deposited on or removed from a surface of a substrate.Thin layers of conducting, semiconducting, and dielectric materials maybe deposited by a number of deposition techniques. Common depositiontechniques in modern processing include physical vapor deposition (PVD),also known as sputtering, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD), and nowelectro-chemical plating (ECP).

[0005] As layers of materials are sequentially deposited and removed,the uppermost surface of the substrate may become non-planar across itssurface and require planarization. Planarizing a surface, or “polishing”a surface, is a process where material is removed from the surface ofthe substrate to form a generally even, planar surface. Planarization isuseful in removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches, and contaminated layers or materials. Planarization is alsouseful in forming features on a substrate by removing excess depositedmaterial used to fill the features and to provide an even surface forsubsequent levels of metallization and processing.

[0006] Chemical mechanical planarization, or chemical mechanicalpolishing (CMP), is a common technique used to planarize substrates. CMPutilizes a chemical composition, typically a slurry or other fluidmedium, for selective removal of material from substrates. Inconventional CMP techniques, a substrate carrier or polishing head ismounted on a carrier assembly and positioned in contact with a polishingpad in a CMP apparatus. The carrier assembly provides a controllablepressure to the substrate urging the substrate against the polishingpad. The pad is moved relative to the substrate by an external drivingforce. The CMP apparatus effects polishing or rubbing movement betweenthe surface of the substrate and the polishing pad while dispersing apolishing composition, or slurry, to effect chemical activity and/ormechanical activity and consequential removal of material from thesurface of the substrate.

[0007] Copper is becoming a metal of choice in ULSI to form theinterconnects that provide the conductive pathway in integrated circuitsand other electronic devices. Copper is a material having advantageousproperties such as lower resistance and better electromigrationperformance compared to traditional materials such as aluminum. Coppercan be deposited by various techniques such as PVD, CVD andelectroplating. Electroplating (ECP) is seen as a low cost and effectivedeposition technique with promise. ECP is performed by introducing asubstrate into a plating bath and applying a current to the substrate.The copper ions plate out of solution and deposit onto the substrate.

[0008] However, copper is difficult to pattern and etch. Accordingly,copper features are formed using damascene or dual damascene processes.In damascene processes, a feature is defined in a dielectric materialand subsequently filled with copper. A barrier layer is depositedconformally on the surfaces of the features formed in the dielectriclayer prior to deposition of the copper. Copper is then deposited overthe barrier layer and the surrounding field. The copper deposited on thefield is removed by CMP processes to leave the copper filled featureformed in the dielectric material. Both abrasive and abrasive free CMPprocesses are available and others are being developed to remove copper.Abrasives refer to additives in the slurry or formed in a polishing padwhich provide mechanical abrasion of a surface being polished. Oneexample of an abrasive is silica particles in a polishing slurry.

[0009]FIG. 1 illustrates the step height of deposited materials, such ascopper, over various features formed on a substrate surface. Forfeatures smaller than 1 μm, the surface of the deposited copper over thefeature is higher than on the field; however, for features larger than 1μm, the field surface is higher. To achieve complete planarization overwide features, it is necessary to deposit a copper thickness ˜1.4-1.6times that of the intra-level dielectric (ILD) thickness. For typicalpower lead levels, a 2.0 μm thick copper layer is required. However, thedeposition of this thick copper layer will limit the throughout of CMP.

[0010] Another problem with CMP of copper is the tendency of coppersurfaces to dish as a result of polishing. Dishing can result fromcopper over-polish used to clear all copper formed on the field acrossthe whole wafer. One area where dishing may occur is in areas whereconductive features exceed five (5) microns. This is particularlyproblematic in some current designs where the conductive features areoften greater than about ten (10) microns. To prevent excessive dishingin these surfaces during CMP processing, oxide pillars are typicallyinterposed in these features to reduce the width of the conductivefeature exposed to CMP processing.

[0011] As a result, there is a need for an apparatus and method fordepositing and planarizing a metal layer, such as a copper layer, on asubstrate.

SUMMARY OF THE INVENTION

[0012] The present invention generally provides method and apparatus fordepositing and planarizing a layer on a substrate using electrochemicaldeposition techniques and polishing techniques.

[0013] In one aspect, the invention provides an apparatus for depositingand planarizing a material on a substrate, comprising a partialenclosure defining a processing region and having a fluid inlet and afluid outlet, a shaft connected to the partial enclosure on one end andto an actuator on an opposing end thereof and adapted to rotate thepartial enclosure, a permeable disc disposed in the partial enclosure, adiffuser plate disposed in the partial enclosure and positioned belowthe permeable disc, and a substrate carrier movably disposed above thepermeable disc, the substrate carrier having a substrate mountingsurface and a plurality of electrical contacts disposed about theperimeter of the substrate receiving surface.

[0014] In another aspect, the invention a processing system for forminga planarized layer on a substrate, comprising a processing platformhaving two or more processing stations, a loading station and asubstrate carrier carousel disposed above the processing stations andthe loading station and a processing apparatus positioned at eachprocessing station, the processing apparatus comprising a partialenclosure defining a processing region and having a fluid inlet and afluid outlet, a shaft connected to the partial enclosure on one end andto an actuator on an opposing end thereof and adapted to rotate thepartial enclosure, a permeable disc disposed in the partial enclosure, adiffuser plate disposed in the partial enclosure and positioned belowthe permeable disc, and a substrate carrier movably disposed above thepermeable disc, the substrate carrier having a substrate mountingsurface and a plurality of electrical contacts disposed about theperimeter of the substrate receiving surface.

[0015] In another aspect, the invention provides a method of processinga substrate, comprising, positioning the substrate in an electrolytesolution a first distance from a permeable disc disposed in theelectrolyte, applying a current to a surface of the substrate exposed tothe electrolyte and depositing a material on the substrate, positioningthe substrate a second distance from the permeable disc, the seconddistance being less than the first distance, and depositing the materialon the substrate at the second distance.

[0016] In another aspect, the invention provides a method of processinga substrate, comprising positioning the substrate in an electrolytesolution a first distance from a permeable disc disposed in theelectrolyte and applying a current to a surface of the substrate exposedto the electrolyte and depositing a material on the substrate.

[0017] In another aspect, the invention provides a method of processinga substrate, comprising positioning the substrate in an electrolytesolution a first distance from a permeable disc disposed in theelectrolyte and depositing a material on the substrate by an electrolessdeposition technique, positioning the substrate a second distance fromthe permeable disc, the second distance being less than the firstdistance, and depositing the material on the substrate at the seconddistance by an electroless deposition technique.

[0018] In another aspect of the invention a method is provided forprocessing a substrate surface, comprising providing a substratecomprising a dielectric layer with feature definitions formed therein, abarrier layer conformally deposited on the dielectric layer and in thefeature definitions formed therein, depositing a copper containingmaterial on the barrier layer while planarizing the copper containingmaterial formed thereon, polishing the substrate surface on a firstplaten to remove residual copper containing materials, polishing thesubstrate surface on a second platen to remove the barrier layer, andbuffing the substrate surface on a third platen to remove defects formedthereon.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] So that the manner in which the above recited features,advantages and objects of the present invention are attained and can beunderstood in detail, a more particular description of the invention,briefly summarized above, may be had by reference to the embodimentsthereof which are illustrated in the appended drawings.

[0020] It is to be noted, however, that the appended drawings illustrateonly typical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

[0021]FIG. 1 is a plot showing step height of a deposited material overvarious features formed in a substrate surface.

[0022]FIG. 2 is a cross sectional view of one embodiment of a processingapparatus of the invention showing a substrate disposed above apermeable disc.

[0023]FIG. 3 is a partial cross sectional view of one embodiment of acarrier head assembly.

[0024]FIG. 4A is a partial perspective view of a plurality of substrateclamps.

[0025]FIG. 4B is a sectional view of one of the substrate clamps takenalong section line 4B-4B of FIG. 4A.

[0026]FIGS. 5A through 5D depict a substrate being secured to thecarrier head assembly

[0027]FIG. 6 depicts a partial view of another embodiment of a carrierhead assembly.

[0028]FIG. 7 depicts a partial view of another embodiment of a carrierhead assembly.

[0029]FIG. 8 is a cross sectional view of another embodiment of aprocessing apparatus of the invention showing a substrate disposed abovea permeable disc.

[0030]FIG. 9 is a cross sectional view of one embodiment of a processingapparatus of the invention showing a substrate disposed above orcontacting a permeable disc

[0031]FIG. 10 is a plan view of one embodiment of a processing platformincorporating embodiments of the processing apparatus of the invention.

[0032]FIG. 11 is a sectional view of a plating station of the platformof FIG. 10.

[0033]FIG. 12 is a schematic perspective view of a chemical mechanicalpolishing apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0034]FIG. 2 is a cross sectional view of one embodiment of an apparatus20 for depositing and planarizing a metal layer on a substrate 22. Oneexample of an apparatus that may be adapted to benefit from theinvention is an ELECTRA™ electroplating tool, available from AppliedMaterials, Inc., of Santa Clara, Calif. An example of a suitableelectroplating tool is described in co-pending U.S. patent applicationSer. No. 09/289,074, filed on Apr. 8, 2000, assigned to common assigneeApplied Materials, Inc., and which is incorporated by reference hereinto the extent not inconsistent with the invention. The apparatus 20generally includes a carrier head assembly 30 movably supported by astanchion 80 over a partial enclosure 34. The stanchion 80 and enclosure34 are generally disposed on a common base 82. The stanchion 80generally includes a base support 84 and a lift mechanism 86. The basesupport 84 extends perpendicularly from the base 82 and may be rotatableon its axis so that the carrier assembly 30 may be moved over thepartial enclosure 34 or to other positions, for example, to otherenclosures or to interface with other processing systems not shown.

[0035] The lift mechanism 86 is coupled to the carrier assembly 30. Thelift mechanism 86 generally controls the elevation of the carrierassembly 30 in relation to the partial enclosure 34. The lift mechanism86 includes be a linear actuator 88, such as a ball screw, lead screw,pneumatic cylinder and the like, and a guide 90 that slides along a rail92. The rail 92 is coupled to the base support 84 by a hinge 94 so thatthe rail 92 of the lift mechanism 86 (i.e., direction of motion) may becontrollably orientated through a range of angles between about 90 toabout 60 degrees relative to horizontal. The lift mechanism 86 and hinge94 allows the carrier assembly 30 holding a substrate 22 to be loweredinto the partial enclosure 34 in various orientations. For example, tominimize the formation of bubbles upon the substrate 22 when interfacingwith fluids disposed within the enclosure 34, the substrate 22 may beorientated at an angle during entry into the partial enclosure 34 andthen rotated to a horizontal orientation once therein.

[0036] The partial enclosure 34 generally defines a container orelectrolyte cell in which an electrolyte or other polishing/depositionfluid can be confined. The electrolyte used in processing the substrate22 can include metals such as copper, aluminum, tungsten, gold, silveror other materials which can be electrochemically deposited onto asubstrate. As one example, copper sulfate (CuSO₄) can be used as theelectrolyte. Copper containing solutions used for plating are availablefrom Shipley Ronel, a division of Rohm and Haas, headquartered inPhiladelphia, Pa., under the tradename Ultrafill 2000.

[0037] The enclosure 34 typically includes an anode 26, a diffuser plate44 and a permeable disc 28 disposed therein. A permeable disc 28, suchas a polishing pad, is disposed and supported in the electrolyte cell onthe diffuser plate 44. The partial enclosure 34 can be a bowl shapedmember made of a plastic such as fluoropolymers, TEFLON®, PFA, PE, PES,or other materials that are compatible with plating chemistries. Thepartial enclosure 34 is connected to a shaft 32 on its lower surfacethat extends below the base 82. Alternatively, the partial enclosure 34can be connected to a mounting platform that is connected to the shaft32. The shaft 32 is connected to an actuator (not shown), such as amotor, e.g., a stepper motor, disposed in the base 82. The actuator isadapted to rotate the partial enclosure 34 about vertical axis x. In oneembodiment, the shaft 32 defines a central passage through which fluidis delivered into the partial enclosure 34 through a plurality of ports36 formed in the shaft 32.

[0038] The anode 26 is positioned at the lower portion of the enclosure34 where it may be immersed in the electrolyte solution. Anode 26 can bea plate-like member, a plate having multiple holes formed therethroughor a plurality of anode pieces disposed in a permeable membrane orcontainer. The anode 26 is preferably comprised of the material to bedeposited, such as copper, nickel, aluminum, gold, silver, tungsten andother materials which can be electrochemically deposited on a substrate.In at least one embodiment, the anode 26 comprises a consumable anodewhich may require periodic replacement. Alternatively, the anode maycomprise non-consumable anode of a material other than the depositedmaterial, such as platinum for a copper deposition.

[0039] In at least one embodiment, the anode 26 is ring-shaped defininga central opening through which the fluid inlet of the shaft 32 isdisposed. In embodiments where the anode 26 is plate-like, a pluralityof holes may be formed through the anode to allow passage of electrolytefluid therethrough. The anode 26 can alternatively be a ring anode, aplate anode, or a chamber confining plating material, including apermeable chamber or other enclosure.

[0040] The permeable disc 28 can be a polishing pad or other type ofvolume spacer which is compatible with the fluid environment and theprocessing specifications. The permeable disc 28 is positioned at anupper end of the partial enclosure 34 and supported on its lower surfaceby the diffuser plate 44. The permeable disc 28 is preferably conductiveto ions in the electrolyte, and as such does not have to be permeable tometal ions, such as copper ions, for example, in copper applications.The metal ions can be supplied from a fluid delivery line 40 having anoutlet 42 positioned above the permeable disc 28. The permeable disk 28may disposed adjacent to or in contact with the anode 26.

[0041] The permeable disk 28 may comprise a plurality of pores of asufficient size and organization to allow the flow of electrolyte to thesubstrate surface while preventing the flow of deposition by-products,such as accelerator and suppressor degradation by-products. Thepermeable disk 28 may also comprise grooves formed therein to assisttransport of fresh electrolyte from the bulk solution into enclosure 34to the gap between the substrate 22 and the permeable disk 28. However,the permeable disc 28 can be permeable to metal ions in someapplications. Typically, the permeable disc 28 may be a polishing padcomprised of polymeric materials, such as polyurethane. Examples ofpolishing pads which can be used include, but are not limited to, an IC1000, an IC 1010, a Suba series pad, a Politex series pad, a MH S seriespad from Rodel, Inc., of Phoenix, Ariz., or a PVDF pad from Asahi ofJapan, or a fixed abrasive pad from 3M, of Minneapolis, Minn.

[0042] The diffuser plate 44 provides support for the permeable disc 28in the partial enclosure 34. The diffuser plate 44 can be secured in thepartial enclosure 34 using fasteners such as screws 38 or other meanssuch as snap or interference fit with the enclosure, being suspendedtherein and the like. The diffuser plate 44 can be made of a materialsuch as a plastic, e.g., fluoropolymer, PE, TEFLON®, PFA, PES, HDPE,UHMW or the like. The diffuser plate 44, in at least one embodiment,includes a plurality of holes or channels 46 formed therein. The holes46 are sized to enable fluid flow therethrough and to provide uniformdistribution of electrolyte through the permeable disc 28 to thesubstrate 22. The permeable disc 28 can be fastened to the diffuserplate 44 using adhesives that are compatible with the fluid environmentand the processing requirements. The diffuser plate 44 is preferablyspaced from the anode 26 to provide a wider process window, thusreducing the sensitivity of plating film thickness to the anodedimensions, and to separate the accelerator and suppressor decompositionby-products, for example, a mono-sulfide compound degraded from anaccelerator, such as bis(3-sulfopropyl) disulfide, C₆H₁₂Na₂O₆S₄,commercially available from the Raschig Corp. of Germany, from a mainplating volume 38 defined between the permeable disc 28 and thesubstrate 22.

[0043] While not shown, a membrane may be disposed between the anode 26and the permeable disc 28 to contain particles produced from the anodefilm from entering the enclosure 34 and depositing as particles on thesubstrate surface. For example, the membrane is permeable to electrolyteflow, but is not typically permeable to accelerator and suppressordegradation by-products on the anode surface.

[0044] The substrate carrier or head assembly 30 is movably positionedabove the permeable disc 28. The substrate carrier assembly 30 isvertically movable above the permeable disc 28 and is laterally movablethereto, for example, the carrier assembly 30 may be rotatable about avertical axis y. The x and y axis of the partial enclosure and the headassembly, respectively, are offset to provide orbital motion between thepermeable disc 28 and the substrate carrier assembly 30. Orbital motionis broadly described herein as an elliptical relative motion between thepermeable disc 28 and the substrate carrier assembly 30. The substratecarrier assembly 30 holds a substrate 22 with the deposition surfacefacing down towards the permeable disc 28. Alternatively, the permeabledisk 28 may comprise a surface which may move in a translational orlinear relative motion as well as rotatable, or circular rotational,relative motion to the substrate carrier assembly 30.

[0045] The substrate carrier assembly 30 generally includes a drivesystem 68, a head assembly 78 and a seat assembly 76. The drive system68 is generally coupled to the guide 90 of the stanchion 80. The drivesystem 68 comprises a column 70 that extends from a power head 56 tosupport the seat assembly 76. The power head 56, which may be anelectric or pneumatic motor, generally provides rotation to the column70 along a central axis. The drive system 86 additionally includes anactuator 54 that is disposed within the column 70 and is coupled to thehead assembly 78. The actuator 54, which may be a lead screw, pneumaticcylinder or other linear actuator, allows the head assembly 78 to movein relation to the seat assembly 76.

[0046] The seat assembly 76 generally includes a plurality of gripperfingers 74 disposed in a polar array about a gripper plate 72. Thegripper plate 72 is coupled to the column 70 so that the gripper plate72 moves with the drive system 68. In one embodiment, three gripperfingers 74 are provided. The gripper fingers 74 generally include a basemember 66, an extension 64 and a contact finger 62. The contact fingers62 are disposed at an angle to the extension 64. The extension 64 iscoupled to the base member 66. The base member 66 is rotatably coupledto the gripper plate 72. The base member 66 generally includes anaperture that aligns with a hole in the gripper plate 72. A clevis pinor other shaft member is disposed through the hole and aperture to allowrotation of the gripper finger 74 in relation to the gripper plate 72.An actuator 60 is coupled between the extension 64 and the gripper plate72. The actuator 60 moves the gripper finger 74 between an open andclosed position. A spring 58 may be optionally disposed on the clevispin to bias the gripper finger 74 towards one position. When the contactfingers 62 are moved inward, a notch 52 disposed at the ends of eachcontact finger 62 defines a seat 50 that is adapted to receive thesubstrate 22 from a transfer robot (not shown). In the inward position,the extensions 64 are disposed at a distance from each other that allowsthe substrate 22 and robot to pass therebetween (See FIG. 5A).

[0047]FIG. 3 depicts one embodiment of the head assembly 78. The headassembly 78 generally includes a housing 302, a stem 304, a supportplate 306 and a plurality of substrate clamps 320 (one of the clamps 320is shown). Generally, the housing 302 includes a hollow shaft 328coupled to the actuator 54 at one end and terminating in a flange 308 atthe opposite end. The flange 308 has a downwardly extending lip 310 thatdefines a central cavity 312.

[0048] The support plate 306 is disposed in the central cavity 312. Thesupport plate 306 has a first side 314 and a second side 316. Thesubstrate 22 is generally disposed proximate the first side 314 duringprocessing. The first side 314 may additionally include one or morevacuum ports 318 disposed therein to restrain the substrate 22 proximatethe first side 314.

[0049] The stem 304 is coupled to a second side 316 of the support plate306. The stem 304 is generally orientated perpendicular to the supportplate 306. The stem 304 may include passages disposed therein to providevacuum or fluid to the first side 314 of the support plate 308 or otherportions of the head assembly 78.

[0050] The substrate clamps 320 are generally comprised of a conductivematerial, such as copper. The substrate clamps 320 are coupled to aconductive ring 322 that electrically couples the individual substrateclamps 320. A screw typically fastens the substrate clamps 320 to theconductive ring 322 although other fasteners or fastening methods may beutilized. The conductive ring 322 generally includes a terminal 324 toallow the ring 322 to be electrically biased by a power source (notshown) coupled to the ring 322 by a lead 326 routed through the housing302.

[0051]FIG. 4A depicts a partial perspective view of the substrate clamps320 extending from the first side 314 of the support plate 306. Thesubstrate clamps 320 are generally disposed in a polar array at theperimeter of the support plate 306. In one embodiment, clamps 320 aremovable relative to the support plate 306 such that a distance which theclamps 320 project from the support plate 306 may be controlled.Generally, the substrate clamps 320 comprise a plurality of first clamps402 and a plurality of second clamps 404 spaced equally about theperimeter of the support plate 306. The first and second clamps 402, 404generally alternate in sequence around the perimeter and are spaced toallow the gripper fingers 74 to pass therebetween. The first clamps 402are generally rectangular in shape and may be optionally curved acrosstheir width to match the diameter of the substrate 22. The second clamps404 are also generally rectangular in shape and may be optionally curvedto match the diameter of the substrate 22. Both the first clamps andsecond clamps 402, 404 have an inner surface 406 that contacts thesubstrate.

[0052] As illustrated in FIGS. 4A and 4B, the clamps 320 are angledoutward to allow the substrate 22 to pass therebetween when extended. Abump 410 disposed on the inner surface of the clamp 320 interfaces witha peripheral surface 412 of the support plate 306. The bump 410 causesthe clamp 320 to flare outwardly when the clamp 320 is extended.Optionally, support surface 306 may include a chamfer 414 to allowsmooth movement of the bump 410 onto the surface 412 of the supportplate 306. The housing 302 generally includes a biasing member disposedradially outward of the clamps 320 that urges the clamps 320 inward. Inone embodiment, the biasing member is a détente pin 416.

[0053] The second clamp 404 generally includes a notch 418 formed on thecontact surface near the tip. The notch 418 has a bottom surface 420that is generally greater in length than the thickness of the substrate22. A wall 422 of the notch 418 closest the end of the first clamp 404is generally chamfered or angled to contact the bevel or rounded edge ofthe substrate 22.

[0054]FIGS. 5A, 5B, 5C and 5D depict the substrate 22 being loaded intothe carrier assembly 30. In FIG. 5A, the gripper fingers 74 are rotatedto form the seat 50 that receives the substrate 22 from the robot notshown. The head assembly 78 is disposed in a first position 502proximate the seat assembly 76. The substrate clamps 322 are fullyextended from the first side 314 of the support plate 308. After therobot is removed leaving the substrate 22 in the seat 50 of the gripperfinger 74, the head assembly 78 is then extended into a second position504 to load the substrate 22 held in the seat 50 between the substrateclamps 322 (See FIG. 5B). The first clamps 402 center the substrate 22relative to the head assembly 78. The clamps 322 are then retractedtowards the support plate 308. The angled wall 422 of the second clamp404 contacts the beveled edge of the substrate 22 and pulls thesubstrate 22 against the support plate 308. The interaction between theangled wall 422 and substrate 22 additionally causes the second clamp404 to flex outwardly against the détente pin 416, displacing the bottomsurface 420 of the notch 418 from the substrate perimeter. The flexedsecond clamp 404 and the détente pin 416 combine to urge the secondclamp 404 inwardly to capture the substrate 22 against the support plate308 while providing good electrical contact between the clamp 404 andsubstrate 22 (See FIGS. 5C and 5D).

[0055] Returning to FIG. 3, the conductive ring 322 is secured to amounting plate 330 that is disposed in the central cavity 312 betweenthe housing 302 and the support plate 306. The mounting plate 330 isgenerally movable relative to the support plate 306 so that the distancethe substrate clamps 320 extend beyond the first side 314 of the supportplate may be controlled. Generally, the mounting plate 330 is biasedaway from the support plate 306 by a spring 332 disposed therebetween.

[0056] To facilitate movement of the mounting plate 330 and substrateclamps 320, the mounting plate 330 is coupled to a sleeve 334 that ismovably disposed around the stem 304. The sleeve 334 has a firstdiameter portion 336 that is sealed against the stem 304 at one end by aseal such as an o-ring 338. The sleeve 334 has a smaller, seconddiameter portion 340 that interfaces with a narrower portion 342 of thestem 304. The narrower portion 342 of the stem 304 is sealed to thesleeve 334 by an o-ring 352, thus creating a piston chamber 344 betweenthe stem 304 and sleeve 334. As fluid, such as air, is applied orevacuated from the chamber 344, the resulting force applied between thesleeve 334 and stem 304 causes the sleeve 334 to move, thuscorrespondingly moving the substrate clamps 320. An outer portion 346 ofthe sleeve 334 is threaded and mates with a corresponding male threadedportion 348 disposed in the mounting plate 330. The amount of threadengagement between the mounting plate 330 and sleeve 334 may be adjustedto set the distance the substrate clamps 320 protrude from the supportplate 306 at a predetermined amount. A set screw 350 in the mountingplate 330 may be tightened to prevent the mounting plate 330 frominadvertently turning about the sleeve 334.

[0057]FIG. 6 depicts a partial view of another embodiment of a substratecarrier assembly 600. The carrier assembly 600 is substantially similarto the carrier assembly 30 described above except wherein a contactplate 602 is disposed on a support plate 604. Generally, the contactplate 602 is disposed on a first side 606 of the support plate 604. Thecontact plate 602 is comprised of a conductive material and is utilizedto bias the substrate 22 during processing. The contact plate 602 iselectrically coupled to a terminal 610 disposed on a second side 612 ofthe support plate 604. The terminal 610 facilitates coupling the contactplate 602 to a power source (not shown) by a lead 608 that is used tobias the substrate 22.

[0058] The contact plate 602 is generally located proximate the edge ofthe substrate 22. The contact plate 602 couples the charge to thesubstrate 22 directly or to a conductive seed layer 620 disposed on thesubstrate surface that wraps around the substrate edge to a portion ofthe substrate backside.

[0059]FIG. 7 depicts another embodiment of a substrate carrier 700. Thesubstrate carrier 700 generally includes a housing 702 defining acentral cavity 704 that is open on a bottom 706 and through at least oneport 708 disposed in the housing 702. The port 708 is typically sized toallow the substrate 22 carried by a robot (not shown) to be placedwithin the cavity 704. A thrust plate 710 is disposed in the housing 702and may be actuated towards the bottom 706 of the housing 702. A ring712 circumscribing the open portion of the bottom 706 includes a ledge714 that supports the substrate 22 as the thrust plate 710 urges thesubstrate 22 against the ring 712. The ring 712 may provide theelectrical contact to bias the substrate 22. Alternatively, the thrustplate 710 may alternatively include a contact plate 716 similar to thecontact plate 602 described in reference to FIG. 6.

[0060]FIGS. 8 and 9 are cross sectional views of an alternativeembodiment of an apparatus 800 of the invention for electrolessdeposition and polishing of a material on the substrate surface. Anelectroless deposition does not normally require the presence of ananode for deposition of a material. In the embodiment shown in FIGS. 8and 9, similar components corresponding to those described in referenceto FIG. 2 are shown and are further described as follows.

[0061] The apparatus 800 discloses an enclosure 834 which typicallyincludes a diffuser plate 844 and a permeable disc 828 disposed thereinin a first relative position 810 adjacent to but vertically displacedfrom substrate 822 disposed in carrier assembly 830 described above inFIG. 2. The permeable disc 828, such as a polishing pad, is disposed andsupported in the electrolyte cell on the diffuser plate 844. The partialenclosure 34 can be a bowl shaped member made of a plastic such asfluoropolymers, TEFLON®, PFA, PE, PES, or other materials that arecompatible with plating chemistries. The enclosure 834 generally definesa container or electrolyte cell in which an electrolyte or otherpolishing/deposition fluid can be confined. The electrolyte used inprocessing the substrate 22 can include metals such as copper, nickel orother materials which can be electroless deposited onto a substrate.

[0062] The electrolyte is circulated into and out of the enclosure 834to provide sufficient concentration of material to the substrate surfacefor processing. The electrolyte is typically provided to the enclosure834 via a fluid delivery line 840 having an outlet 842 positioned abovethe permeable disk 828. The electrolyte outlet from the enclosure 834 isnot shown. In one aspect, the partial enclosure 834 can be initiallyfilled with electrolyte prior to substrate processing and can thencirculate the electrolyte into and out of the partial enclosure.

[0063]FIG. 8 shows the substrate 822 and the permeable disk 828 in afirst position 810 generally relative to one another. The first position810 typically has a distance between about 1 and about 5 mm between thepermeable disk 828 and the substrate 822. In one aspect of theinvention, a distance of about 2 mm between the permeable disk 828 andthe substrate 822 is used.

[0064]FIG. 9 shows the permeable disk 828 and the substrate 822 adjacentto or in near contact with one another in the second position 820. Thesecond position is generally about 100 μm or less, including contact,between the permeable disk 828 and the substrate 822.

[0065]FIGS. 10 and 11 depicts a processing apparatus 1000 having atleast one plating station 1002 and at least one conventional polishingor buffing station 1006. One polishing tool that may be adapted tobenefit from the invention is a MIRRA® chemical mechanical polisheravailable from Applied Materials, Inc. located in Santa Clara, Calif.The exemplary apparatus 1000 generally comprises a factory interface1008, a loading robot 1010, and a depositing and planarizing module1012. Generally, the loading robot 1010 is disposed proximate thefactory interface 1008 and the depositing and planarizing module 1012 tofacilitate the transfer of substrates 22 therebetween.

[0066] The factory interface 1008 generally includes a cleaning module1014 and one or more wafer cassettes 1016. An interface robot 1018 isemployed to transfer substrates 22 between the wafer cassettes 1016, thecleaning module 1014 and an input module 1020. The input module 1020 ispositioned to facilitate transfer of substrates 22 between thedepositing and planarizing module 1012 and the factory interface 1008 bythe loading robot 1010. For example, unprocessed substrates 22 retrievedfrom the cassettes 1016 by the interface robot 1018 may be transferredto the input module 1020 where the substrates 22 may be accessed by theloading robot 1010 while processed substrates 22 returning from thedepositing and planarizing module 1012 may be placed in the input module1020 by the loading robot 1010. Processed substrates 22 are typicallypassed from the input module 1020 through the cleaning module 1014before the factory interface robot 1018 returns the cleaned substrates22 to the cassettes 1016. An example of such a factory interface 1008that may be used to advantage is disclosed in U.S. patent applicationSer. No. 09/547,189, filed Apr. 11, 2000, assigned to common assigneeApplied Materials, Inc., and which is hereby incorporated by reference.

[0067] The loading robot 1010 is generally positioned proximate thefactory interface 1008 and the depositing and planarizing module 1012such that the range of motion provided by the robot 1010 facilitatestransfer of the substrates 22 therebetween. An example of a loadingrobot 1010 is a 4-Link robot, manufactured by Kensington Laboratories,Inc., located in Richmond, Calif. The exemplary loading robot 1010 has agripper 1011 that may orientate the substrate 22 in either a vertical ora horizontal orientation.

[0068] The exemplary depositing and planarizing module 1012 has atransfer station 1022 and a carousel 1034 in addition to the platingstation 1002 and the polishing station 1006, all of which are disposedon a machine base 1026. The depositing and planarizing module 1012 maycomprise one polishing module and two plating modules. Alternatively,the depositing and planarizing module 1012 may comprise one platingmodule and two polishing modules. In a further alternative, a polishingmodule 1120 may be provided for polishing a substrate followingprocessing by the methods described herein or in the apparatus describedherein.

[0069] In one embodiment, the transfer station 1022 comprises at leastan input buffer station 1028, an output buffer station 1030, a transferrobot 1032, and a load cup assembly 1024. The loading robot 1010 placesthe substrate 22 onto the input buffer station 1028. The transfer robot1032 has two gripper assemblies, each having pneumatic gripper fingersthat grab the substrate 22 by the substrate's edge. The transfer robot1032 lifts the substrate 22 from the input buffer station 1028 androtates the gripper and substrate 22 to position the substrate 22 overthe load cup assembly 1034, then places the substrate 22 down onto theload cup assembly 1024. An example of a transfer station that may beused to advantage is described by Tobin in U.S. patent application Ser.No. 09/314,771, filed Oct. 10, 1999, assigned to common assignee AppliedMaterials, Inc., and which is hereby incorporated by reference.

[0070] The carousel 1034 is generally described in U.S. Pat. No.5,804,507, issued Sep. 8, 1998 to Tolles et al. and is herebyincorporated herein by reference in its entirety. Generally, thecarousel 1034 is centrally disposed on the base 1026. The carousel 1034typically includes a plurality of arms 1036. The arms 1036 generallyeach supporting a polishing head 1038 while one arm supports a carrierhead assembly 1004. One of the arms 1036 depicted in FIG. 10 is shown inphantom such that the transfer station 1022 may be seen. The carousel1034 is indexable such that the polishing head 1038 and carrier head1004 may be moved between the modules 1002, 1006 and the transferstation 1022.

[0071] Generally the polishing head 1038 retains the substrate 22 whilepressing the substrate against a polishing material (not shown) disposedon the polishing stations 1006. The polishing station 1006 generallyrotates to provide a relative motion between the substrate 22 retainedby the polishing head 1038 and the polishing material. Typically, apolishing fluid is provided to assist in the material removal from thesubstrate 22. One polishing head that may be utilized is a TITAN HEAD™wafer carrier manufactured by Applied Materials, Inc., Santa Clara,Calif.

[0072]FIG. 11 depicts a sectional view of the substrate carrier headassembly 1004 supported above the plating station 1006. In oneembodiment, the substrate carrier head assembly 1004 is substantiallysimilar to the substrate carrier assembly 30 described above. Similarly,the plating station 1006 includes a partial enclosure 1102 that definesan electrolyte cell to facilitate metal deposition on the substrate 22that is substantially similar to the enclosure 30 described above. Theenclosure 1102 of the plating station 1006 is coupled to a motor thatprovides rotation of the enclosure 1102.

[0073] The arrangement of the plating stations 1006 and polishingstations 1002 on the depositing and planarizing module 1012 allow forthe substrate 22 to be sequentially plated or polishing by moving thesubstrate between stations. The substrate 22 may be processed in eachstation 1002, 1006 while remaining in it respective head or carrier1038, 1004, or the substrate may be switched between heads by offloadingthe substrate from one head into the load cup and loading into thesubstrate into the other polishing head. Optionally, the depositing andplanarizing module 1012 may comprise only one type of head may beutilized (i.e., all polishing heads 1038 or all carrier heads 1004).

[0074]FIG. 12 is a schematic perspective view of a chemical mechanicalpolishing apparatus 1120 for further processing substrate followingprocessing by the method described herein or in the apparatus describedherein. The polishing apparatus 1120 includes a lower machine base 1122with a table top 1128 mounted thereon and a removable outer cover (notshown). The table top 1128 supports a series of polishing stations,including a first polishing station 1125 a, a second polishing station1125 b, a final polishing station 1125 c, and a transfer station 1127.The transfer station 1127 serves multiple functions, including, forexample, receiving individual substrates 1110 from a loading apparatus(not shown), washing the substrates, loading the substrates into carrierheads 1180, receiving the substrates 1110 from the carrier heads 1180,washing the substrates 1110 again, and transferring the substrates 1110back to the loading apparatus.

[0075] Each polishing station 1125 a-1125 c includes a rotatable platen1130 having a polishing pad 1100 disposed thereon. Each platen 1130 maybe a rotatable aluminum or stainless steel plate connected to a platendrive motor (not shown). The polishing pads 1100 may compride aconventional polishing or a fixed abrasive polishing pad, e.g., apolishing pad comprising abrasive particle in a binder polymericmaterial. Alternatively, an abrasive slurry may be provided to aconventional polishing pad for processing. Further, an abrasive freecomposition may be applied to convention pad to enact polishing of asubstrate disposed thereon.

[0076] The polishing stations 1125 a-1125 c may include a padconditioner apparatus 1140. The pad conditioner apparatus 1140 has arotatable arm 1142 holding an independently rotating conditioner head1144 and an associated washing basin 1146. The pad conditioner apparatus1140 maintains the condition of the polishing pad so that it willeffectively polish the substrates. Each polishing station may include aconditioning station if the CMP apparatus is used with other padconfigurations.

[0077] The polishing stations 1125 a-1125 c may each have a slurry/rinsearm 1152 that includes two or more supply tubes to provide one or morechemical slurries and/or water to the surface of the polishing pad. Theslurry/rinse arm 1152 delivers the one or more chemical slurries inamounts sufficient to cover and wet the entire polishing pad. Eachslurry/rinse arm 1152 also includes several spray nozzles (not shown)that can provide a high-pressure fluid rinse on to the polishing pad atthe end of each polishing and conditioning cycle. Furthermore, two ormore intermediate washing stations 1155 a, 1155 b, and 1155 c may bepositioned between adjacent polishing stations 1125 a, 1125 b, and 1125c to clean the substrate as it passes from one station to the next.

[0078] A rotatable multi-head carousel 1160 is positioned above thelower machine base 1122. The carousel 1160 includes four carrier headsystems 1170 a, 1170 b, 1170 c, and 1170 d. Three of the carrier headsystems receive or hold the substrates 1110 by pressing them against thepolishing pads 1100 disposed on the polishing stations 1125 a-1125 c.One of the carrier head systems 1170 a-1170 d receives a substrate fromand delivers a substrate 1110 to the transfer station 1127. The carousel1160 is supported by a center post 1162 and is rotated about a carouselaxis 1164 by a motor assembly (not shown) located within the machinebase 1122. The center post 1162 also supports a carousel support plate1166 and a cover 1168.

[0079] The four carrier head systems 1170 a-1170 d are mounted on thecarousel support plate 1166 at equal angular intervals about thecarousel axis 1164. The center post 1162 allows the carousel motor torotate the carousel support plate 1166 and orbit the carrier headsystems 1170 a-1170 d about the carousel axis 1164. Each carrier headsystem 1170 a-1170 d includes one carrier head 1180. A carrier driveshaft 1178 connects a carrier head rotation motor 1176 (shown by theremoval of one quarter of the cover 1168) to the carrier head 1180 sothat the carrier head 1180 can independently rotate about its own axis.There is one carrier drive shaft 1178 and motor 1176 for each head 1180.In addition, each carrier head 1180 independently oscillates laterallyin a radial slot 1172 formed in the carousel support plate 1166.

[0080] The carrier head 1180 performs several mechanical functions.Generally, the carrier head 1180 holds the substrate 1110 against thepolishing pad 1100, evenly distributes a downward pressure across theback surface of the substrate 1110, transfers torque from the driveshaft 1178 to the substrate 1110, and ensures that the substrate 1110does not slip out from beneath the carrier head 1180 during polishingoperations.

[0081] In one embodiment of the apparatus 1120, the table top 1128supports a series of polishing stations, including a first polishingstation 1125 a adapted for polishing or removing residual material, suchas copper, deposited to fill features formed on a substrate surface, asecond polishing station 1125 b adapted for polishing or removingbarrier layer material, such as tantalum or tantalum nitride from asubstrate surface, and a final polishing station 1125 c adapted forbuffing the substrate surface to remove surface defects formed on thesubstrate surface. Additionally, a cleaning module 1014 may be disposedon or adjacent to the apparatus 1120 for further treatment to removesurface defects formed during substrate processing and handling.

1. A method of processing a substrate, comprising: a) positioning thesubstrate in an electrolyte solution a first distance from a permeabledisc disposed in the electrolyte; b) applying a current to a surface ofthe substrate exposed to the electrolyte and depositing a material onthe substrate; and c) positioning the substrate a second distance fromthe permeable disc, the second distance being less than the firstdistance.
 2. The method of claim 1, wherein the electrolyte is a coppercontaining solution.
 3. The method of claim 2, wherein less than 5000angstroms of material is deposited at the first distance.
 4. The methodof claim 1, wherein the current is applied in a range from about 20 ampsor less.
 5. The method of claim 1, wherein the permeable disc is apolishing pad.
 6. The method of claim 5, wherein applying the current tothe substrate comprises the use of a pulse plating technique.
 7. Themethod of claim 1, wherein the first distance is between about 1 mm andabout 5 mm.
 8. The method of claim 7, wherein the second distance isless than about 100 μm.
 9. The method of claim 7, wherein the substrateand the permeable disk are in contact at the second distance.
 10. Themethod of claim 1, further comprising transferring the substrate to apolishing apparatus.
 11. The method of claim 9, wherein the permeabledisk exerts a pressure on the substrate of about 2 psi or less at thesecond distance.
 12. The method of claim 1, wherein the current isapplied in a range between about 0.5 amps and about 5.0 amps.
 13. Amethod of processing a substrate, comprising: positioning the substratein an electrolyte solution a first distance from a permeable discdisposed in the electrolyte; and applying a current to a surface of thesubstrate exposed to the electrolyte and depositing a material on thesubstrate.
 14. The method of claim 13, wherein the electrolyte is acopper containing solution.
 15. The method of claim 13, wherein lessthan 5000 angstroms of material is deposited at the first distance. 16.The method of claim 13, wherein the current is applied in a range fromabout 20 amps or less.
 17. The method of claim 13, wherein the permeabledisc is a polishing pad.
 18. The method of claim 13, further comprisingtransferring the substrate to a polishing apparatus.
 19. The method ofclaim 13, wherein the current is applied in a range between about 0.5amps and about 5.0 amps.